﻿/**********************************************************************
 * Copyright (c) 2008, j. montgomery                                  *
 * All rights reserved.                                               *
 *                                                                    *
 * Redistribution and use in source and binary forms, with or without *
 * modification, are permitted provided that the following conditions *
 * are met:                                                           *
 *                                                                    *
 * + Redistributions of source code must retain the above copyright   *
 *   notice, this list of conditions and the following disclaimer.    *
 *                                                                    *
 * + Redistributions in binary form must reproduce the above copyright*
 *   notice, this list of conditions and the following disclaimer     *
 *   in the documentation and/or other materials provided with the    *
 *   distribution.                                                    *
 *                                                                    *
 * + Neither the name of j. montgomery's employer nor the names of    *
 *   its contributors may be used to endorse or promote products      *
 *   derived from this software without specific prior written        *
 *   permission.                                                      *
 *                                                                    *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS*
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT  *
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS  *
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE     *
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,*
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES           *
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 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) *
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,*
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)      *
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED*
 * OF THE POSSIBILITY OF SUCH DAMAGE.                                 *
 **********************************************************************/
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

using System.Security.Cryptography;

namespace UpdateDnsOMatic.Utility
{
    internal class CryptoUtility
    {
        internal string EncryptData(string dataToEncrypt)
        {
            return this.EncryptData(Encoding.UTF8.GetBytes(dataToEncrypt));
        }

        private string EncryptData(byte[] dataToEncrypt)
        {
            try
            {
                byte[] encodedPlaintext = dataToEncrypt;
                byte[] encodedEntropy = Encoding.UTF8.GetBytes(
                  AssemblyInfo.Instance.AssemblyTitle);

                byte[] ciphertext = ProtectedData.Protect(encodedPlaintext,
                  encodedEntropy, DataProtectionScope.LocalMachine);

                return Convert.ToBase64String(ciphertext);
            }
            catch (CryptographicException ce)
            {
                throw new ApplicationException("Error encrypting ciphertext: " + ce.ToString());
            }
        }

        internal string DecryptData(string ciphertextString)
        {
            try
            {
                byte[] ciphertext = Convert.FromBase64String(ciphertextString);
                byte[] encodedEntropy = Encoding.UTF8.GetBytes(
                  AssemblyInfo.Instance.AssemblyTitle);

                byte[] encodedPlaintext = ProtectedData.Unprotect(ciphertext,
                  encodedEntropy, DataProtectionScope.LocalMachine);

                return Encoding.UTF8.GetString(encodedPlaintext);
            }
            catch (CryptographicException ce)
            {
               throw new ApplicationException("Error decrypting ciphertext: " + ce.ToString());
               // return string.Empty;
            }
        }
    }
}
